Eyes of fishes and birds, with special reference to tapeta lucida or reflectors, are being investigated. Specific inquiries are: identification of melanoid pigments in the tapeta of catfish and gar and the nature of the reflecting materials in situ; chemistry and organization of the tapetum lucidum of snook; the ultrastructure and reflective properties of guanine tapeta of anchovies; spectrum reflectance of tapeta lucida; characterization of rod visual pigments; and measurements of retinal densities of the above mentioned fishes. Spectrodiometric measurements of underwater illumination will be made in regions frequented by these fishes. The several kinds of data will be used to interpret the functioning of tapeta and the role the latter play in the vision of fishes inhabiting turbid and poorly illuminated waters. Photoreceptors and the pigment epithelium of wrasses will be investigated to establish the nature of the cones present, and the nature of the red screening pigment in the epithelium. Another study will deal with the lipid tapeta lucida of nocturnal birds (Caprimulgiformes) with a view to identifying the kind of reflecting material present and describing the ultrastructure of the photoreceptors and the pigment epithelium.